The present invention relates to a steering system for a tracked vehicle and, more specifically, to a brake-actuating steering and braking control system.
Turning a tracked vehicle is generally affected by controlling relative movement between two laterally spaced endless tracks of the vehicle. Basically, the track on a side of the vehicle corresponding to the direction of an intended turn is slowed relative to the track on the opposite side of the vehicle. As such, the vehicle performs a turn about the relatively slower track.
Previous steering systems for tracked vehicles have tended to be somewhat cumbersome, since the steering controls for these systems have been in the form of hand-controlled lever actuators. These types of control systems are generally awkward for the user, especially in complex maneuvering or for a beginner.
Differential steering systems have been developed to facilitate operation (steering) tracked vehicles, since these systems may be equipped with more user-friendly steering wheels. Differential steering systems vary the input to the tracks from respective drive motors and/or clutches to alter the magnitude of power delivered to each track relative to each other. To accomplish this, these systems generally require the use of a complex and expensive processor and feedback system to coordinate the relative operation of the different drive motors and/or clutches. Typical differential steering systems are described in U.S. Pat. No. 5,948,029 and 6,039,132.
An alternative to the differential steering system is described in U.S. Pat. No. 4,702,358. This system uses a processor and feedback system similar the differential steering systems described above to control relative clutching and braking of the separate drive assemblies for the tracks of the vehicle. Similar to the differential steering systems described above, however this system is complex and costly. Operation of this steering system (by the user) requires the manipulation of a tiller bar for steering control, which, as stated above, is awkward to operate.
Furthermore, tracked vehicles utilizing previous steering control systems for tracked vehicles have required separate (i.e., independent) braking systems, as the steering and braking systems were not cooperable with each other. In other words, processor controlled steering systems have required entirely separate braking systems (usually hydraulic systems), increasing the vehicle""s cost and complexity.
The present invention avoids these limitations by providing a brake-actuating steering and braking control system for a tracked vehicle having right and left side track assemblies. The system includes a braking control subsystem, a steering control subsystem, and right and left side brake-actuating subsystems.
Each of the right and left side brake-actuating subsystems includes a respective one of right and left side brake mechanisms. Each of the right and left side brake mechanisms are coupled to a respective one of the right and left side track assemblies of the tracked vehicle and are constructed and arranged to brakingly engage respective right and left side track assemblies with a braking force proportional to an amount of fluid under pressure delivered thereto to thereby stop or at least slow respective track assemblies.
The braking control subsystem including a brake pedal is depressibly displaceable by a user. The braking control subsystem is communicated with each of the right and left side brake-actuating subsystems. Each of the right and left side brake mechanisms is actuated proportionally to a magnitude of displacement of the brake pedal by the user. Upon actuation, the right and left side track assemblies (and, as such the vehicle itself) are slowed (or stopped altogether) proportionally to the displacement magnitude of the brake pedal.
The steering control subsystem includes a steering wheel, which is rotatably displaceable by a user in clockwise and counter-clockwise directions. The steering control subsystem is communicated with each of the right and left side brake-actuating subsystems such that a corresponding one of the right and left side brake mechanisms is actuated proportionally to the magnitude of displacement of the steering wheel by the user. Upon actuation of the steering control subsystem, one of the track assemblies, according to the direction of displacement of the steering wheel, is stopped or at least slowed. Therefore, the tracked vehicle turns in a direction determined by the direction of displacement of the steering wheel within a radius determined by the magnitude of displacement of the steering wheel.
The steering and braking control system of the present invention provides user-friendly controls (steering wheel and brake pedal) and a simplified design, relative to previous systems. Furthermore, as the steering and braking control system affects steering and braking control of the tracked vehicle without using the processor and feedback systems of previous designs described above, the present invention is further simplified and provides a cost-effective alternative.